JP2000352875A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a leak of the developer in a developing device that a blade is adopted as developer layer thickness controlling means. SOLUTION: This developing device is provided with a feeding roller feeding the developer on the developing roller, a casing that the developing roller and the feeding roller is fitted in freely rotationally, blade shape developer layer thickness controlling means 22 fitted to the casing, for controlling the layer thickness of the developer being fed on the developing roller, a sheet material arranged on the downstream side in the rotary direction of the developing area of a photoreceptor on the developing roller and on the rotary direction upstream side of the position press contact with the feeding roller, for preventing the leak of the developer uniformly held in contact with the developing roller in the lengthwise direction of the developing roller, and developer sealing means 37 consisting of elastic material for preventing the leak of the developer, attached in one body with developer layer thickness controlling means 22 on both end part of the position that the developer layer thickness controlling member 22 is press contact with the developing roller in one body with the developer layer thickness controlling member 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a developing device for developing an electrostatic latent image in an electronic copying apparatus such as a printer.

[0002]

2. Description of the Related Art Conventionally, a developing device using a one-component developer has a detector (hereinafter referred to as "toner") concentration detecting device and a control device which are different from those using a two-component developer. It is unnecessary, and no carrier adheres to the latent image carrier during development.Even if the latent image carrier is cleaned with a blade after transferring the visible image, cleaning is easy without damaging the surface of the latent image carrier. Can do
There are advantages such as simplification and miniaturization of the device can be easily achieved.

[0003] However, a developing device using a one-component developer has such an advantage. However, since there is no such thing as a carrier that is attracted to magnetism, an uncharged toner (developer) is applied to an end of a developing roller. There is a problem of leakage from the part.

At present, in a developing apparatus using a one-component developer, an elastic foaming agent such as urethane foam is generally used as a means for sealing the toner. When an elastic foaming agent is used, there is an advantage that the gap between the developing roller, the casing, and the layer thickness regulating means is easily filled because the elasticity is large.

[0005]

However, when an elastic foaming agent is used as the sealing means, it is difficult to seal the sharp gap, and particularly, the R layer of the developing roller and the developer layer thickness regulating means as a blade. Cannot fill the wedge-shaped gap formed by the R portion. Further, since the sealing means is attached to the casing, it is difficult to determine the positions of the sealing means and the layer thickness regulating means. Furthermore, when sticking a sealing means, a sealing means expands and cannot be stuck at a regular position.

[0006] For these reasons, there is still a problem that toner leakage occurs. In addition, since a sealing material such as a sponge is attached to the inside of the casing, there is a problem that workability is poor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing device in which a blade is used as a developer layer thickness regulating means, in which leakage of the developer can be prevented.

[0008]

In order to solve this problem, a developing device of the present invention supplies a developer to an electrostatic latent image formed on a photoreceptor to visualize the electrostatic latent image. A developing roller, a supply roller that supplies the developer to the developing roller, a casing in which the developing roller and the supply roller are rotatably mounted and the developer is stored, and a casing that is pressed against and contacts the developing roller. A plate-like developer layer thickness regulating means for regulating the layer thickness of the developer supplied to the developing roller, and a pressure contact position between the developing roller and the supply roller at a position downstream of the developing region of the photoconductor in the rotation direction with respect to the developing roller. A sheet material disposed upstream in the rotation direction and uniformly abutting in the longitudinal direction of the developing roller to prevent leakage of the developer; and a developer layer thickness in the developing roller integrally attached to the developer layer thickness regulating means. Control means are provided at both ends of the position where the pressure contact is obtained by a structure having a developer sealing means for preventing leakage of the developer of an elastic material.

Thus, the gap generated between the developer layer thickness regulating means and the developing roller can be filled.
It is possible to prevent the developer from leaking in the developing device using the blade as the developer layer thickness regulating means.

Further, since it is not necessary to attach the developer sealing means, it is possible to improve the workability and reduce the number of work steps.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a developing roller for supplying a developer to an electrostatic latent image formed on a photoreceptor to visualize the electrostatic latent image; A supply roller that supplies the developer to the developing roller, a casing in which the developing roller and the supply roller are rotatably mounted and the developer is stored, and a casing that is attached to the casing so as to press and contact the developing roller. A plate-like developer layer thickness regulating means for regulating the layer thickness of the supplied developer, and a rotational direction downstream of the developing region of the photoconductor in the developing roller and a rotationally upstream side of the pressure contact position with the supply roller. A sheet material that is disposed and uniformly abuts in the longitudinal direction of the developing roller to prevent leakage of the developer, and is integrally attached to the developer layer thickness regulating means, so that the developer layer thickness regulating means of the developing roller is in pressure contact. Do A developer sealing means provided at both ends of the device and made of an elastic material to prevent leakage of the developer, and fills a gap generated between the developer layer thickness regulating means and the developing roller. Therefore, there is an effect that it is possible to prevent the leakage of the developer in the developing device using the blade as the developer layer thickness regulating means. Further, since it is not necessary to attach the developer sealing means, it is possible to improve the workability and reduce the number of work steps.

According to a second aspect of the present invention, there is provided a developing device according to the first aspect, wherein both ends of the developer layer thickness regulating means are fitted and fixed to the developer sealing means. This has the effect that the gap between the developer layer thickness regulating means and the developer sealing means can be reliably filled.

According to a third aspect of the present invention, in the first or the second aspect of the present invention, a gap is provided between the developer sealing means and the casing within a layer thickness regulation range by the developer layer thickness regulation means. Is formed, and the developer layer thickness regulating means is not affected by the casing via the developer sealing means, so that a uniform layer thickness can be stably formed. Has an action.

According to a fourth aspect of the present invention, there is provided a developing device according to any one of the first to third aspects, wherein the developer sealing means and the casing are fixed by uneven fitting. This has the effect of facilitating the incorporation and reassembly of the developer sealing means into the casing and of preventing leakage of the developer at the joint between the two.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, a coefficient of friction of a portion of the developer sealing means which comes into contact with the developing roller has a dynamic friction coefficient. A developing device that is 0.1 to 0.8,
This has an effect that it is possible to prevent a problem that the developer enters between the developer sealing means and the developing roller and a load torque of the apparatus increases.

According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the developer sealing means is provided with a convex which is orthogonal to the developing roller axis and inclined inward. The developing rib is formed on the inner peripheral side in contact with the developing roller, and the developer sealing means comes into contact with the developing roller at the edge of the protruding rib, so that the contact area between them is minimized, This has the effect of preventing an increase in load torque and an increase in frictional heat.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the convex rib portion is inclined so that the developer is pushed back inside the casing and is provided inside the developer sealing means. The developing device has the function of preventing the same developer from staying around the developer sealing means and preventing the developer from sticking due to frictional heat.

According to an eighth aspect of the present invention, in the sixth or seventh aspect, the developer layer thickness regulating means and the convex rib portion are formed on the same circumference with respect to the developing roller. And a gap between the developer sealing means and the developing roller and a gap between the developer layer thickness regulating means and the developing roller are prevented.

According to a ninth aspect of the present invention, in the invention according to any one of the sixth to eighth aspects, the convex rib portion is provided on the upstream side with respect to the rotation of the developing roller. The developing device is formed outside the layer thickness regulating range of the layer thickness regulating unit, and the downstream side is a developing device formed inside the layer thickness regulating range of the developer layer thickness regulating unit, and includes a developer sealing unit and a developer layer thickness regulating unit. Has the effect that the developer leaking from the end of the developer layer thickness regulating means through the gap between the two can be returned into the casing.

According to a tenth aspect of the present invention, in the invention according to any one of the sixth to ninth aspects, the leading end of the sheet material is disposed so as to contact the surface longitudinal direction of the developing roller, The sheet material and the convex rib portion are a developing device having an area that also intersects with the circumferential direction of the developing roller, so that the developer sealing means is prevented from being removed due to the friction of the developing roller and cannot be sealed, This has the effect that the gap between the sheet material and the developer sealing means can be reliably filled.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is an explanatory view showing an image forming apparatus equipped with a developing device according to an embodiment of the present invention.
3 is a sectional view showing a process unit including a developing device attached to the image forming apparatus of FIG. 1, FIG. 3 is an enlarged sectional view showing a main part of FIG. 2, and FIG. 4 is attached to the image forming apparatus of FIG. FIG. 5 is a perspective view showing another example of the toner seal means and the blade, FIG. 5 is a perspective view showing another example of the toner seal means and the blade attached to the image forming apparatus of FIG. 1, and FIG. FIG. 7 is a perspective view showing still another example of the attached toner seal means and blade, FIG. 7 is a perspective view showing still another example of the toner seal means and blade attached to the image forming apparatus of FIG. 1, and FIG. 7 is an enlarged perspective view showing a main part of FIG. 7, and FIG. 9 is a plan view of FIG.

As shown in FIG. 1, the image forming apparatus of the present embodiment has four image forming stations 1a, 1b,
1c and 1d are arranged. Each of the image forming stations 1a, 1b, 1c, 1d has a photosensitive drum (photosensitive member) 2a, 2b, 2c, 2d as an image carrier, and around the photosensitive drums 2a, 2b. , 2
charging means 3a, 3 for uniformly charging the surfaces of c and 2d
b, 3c, 3d, developing means 4a for visualizing the electrostatic latent image,
4b, 4c, 4d, cleaning means 5a, 5b, 5c, 5d for removing residual toner, and exposure means 6a of a scanning optical system for irradiating light corresponding to image information to each of the photosensitive drums 2a, 2b, 2c, 2d. , 6b, 6c, 6d, and transfer means 8a, 8b, 8c, 8d for transferring a toner image to an intermediate transfer belt (transfer material) 12 constituting the transfer means 7.

Here, the image forming stations 1a, 1
b, 1c, and 1d form a yellow image, a magenta image, a cyan image, and a black image, respectively.
a, 6b, 6c, and 6d, exposure light 9 corresponding to a yellow image, a magenta image, a cyan image, and a black image.
a, 9b, 9c, and 9d are output.

Each image forming station 1a, 1b, 1
c, 1d, the photosensitive drums 2a, 2b,
An endless belt-shaped intermediate transfer belt 12 supported by rollers 10 and 11 is disposed below 2c and 2d, and rotates in the direction of arrow A.

The sheet material 17 stored in the sheet cassette 16 is fed by a sheet feeding roller 18 and is discharged to a sheet discharge tray (not shown) via a sheet material transfer roller 19 and a fixing unit 20. You.

In the color image forming apparatus having the above-described structure, first, in the image forming station 1d, image information is stored on the photosensitive drum 2d by a known electrophotographic process using a charging unit 3d and an exposing unit 6d. A latent image of a black component color is formed. Then, the developing means 4
In step d, a visible image is formed as a black toner image by the developer having the black toner, and the transfer unit 8d transfers the black toner image to the intermediate transfer belt 12.

On the other hand, while the black toner image is being transferred to the intermediate transfer belt 12, the image forming station 1c
To form a latent image of a cyan component color, and a developing unit 4c visualizes a cyan toner image of the cyan toner, which is transferred by a transfer unit 8c, and is transferred to the black toner previously transferred onto the intermediate transfer belt 12. Superimposed on the image.

Thereafter, image formation is performed in the same manner for the magenta toner image and the yellow toner image. When the superposition of the four color toner images on the intermediate transfer belt 12 is completed, the paper feed roller 16 feeds the paper cassette 16. Sheet transfer roller 19 on sheet material 17 such as paper taken out of
Thus, the toner images of four colors are collectively transferred and conveyed, and are heated and fixed by the fixing unit 20, so that a full-color image is obtained on the sheet material 17.

Each of the photosensitive drums 2a, 2b, 2c, and 2d, to which the transfer has been completed, is connected to a cleaning unit 5a,
At 5b, 5c, and 5d, the residual toner is removed, and the printing operation is completed in preparation for the subsequent image formation.

As shown in FIGS. 2 and 3, a photosensitive drum 3 on which an electrostatic latent image is formed is provided on a casing 30 of a process unit attached to such an image forming apparatus.
1. charging means 33 for uniformly charging the surface of the photosensitive drum 31; developing roller 21 for supplying toner to the photosensitive drum 31 to visualize an electrostatic latent image; A blade 22 that is provided in parallel pressure contact to reduce the thickness of the toner attached to the developing roller 21, and a toner supply roller (supply roller) that supplies the toner that has been taken out of the toner cartridge 34 and agitated by the agitator 35 to the developing roller 21. ) 23 is rotatably mounted.

A cleaning means 32 for cleaning the outer peripheral surface of the photosensitive drum 31 is provided on the casing 30.
Is attached.

Then, the developing roller 21 and the toner supply roller 23 rotate in the same direction, and
Rotates in the opposite direction.

The axis between the developing roller 21 and the toner supply roller 23 is located between the developing roller 21 and the toner supply roller 23.
Is smaller than the sum of the radii. The pressing amount here is about 0.3 to 1.5 mm.

The developing roller 21 is formed by integrally molding an elastic body such as silicon rubber or polyurethane rubber, which is made conductive by adding carbon on the outer periphery of the metal shaft, to a thickness of about 0.5 to 4 mm. Volume resistance value is 10
It is designed to be about ² Ωcm to 10 ⁷ Ωcm. The toner supply roller 23 is formed by integrally molding urethane foam or the like on the outer periphery of a metal shaft.

The toner cartridge 34 stores a non-magnetic one-component toner.
Dropped inside. Then, the toner is stirred by the agitator 35 to prevent blocking of the toner and to convey the toner to the toner supply roller 23.

The toner supply roller 23 includes a developing roller 21
The toner is rotated with a relative speed difference from the developing roller 21 so that toner adheres to the developing roller 21 at a contact portion with the developing roller 21 and scrapes off residual toner on the developing roller 21 after the development is completed. The scraped toner is mixed with unused toner in the casing 30 and reused.

The blade 22 is a toner layer thickness regulating member (developing agent layer thickness regulating means) having an elastic rubber member, and has a free end and the other end fixed to plate-like elastic support members 24 and 25.

The blade 22 is made of a metal such as a phosphor bronze plate or a stainless spring material. The rubber member 22a attached to the free end has an arc-shaped cross section and is pressed against the peripheral surface of the developing roller 21 by an arc-shaped portion. are doing.

The rubber member 22a is made of a material separated from the toner in the triboelectric charging order in order to charge the toner. For example, a resin material such as silicone rubber, Teflon rubber, polyimide rubber, polyester rubber, urethane rubber is used. The main component.

The developing roller 2 is driven by the toner supply roller 23.
The toner supplied to 1 has a layer thickness regulated on the developing roller 21 by the blade 22 and is charged to the same polarity as the electrostatic latent image. Then, the charged toner comes into contact with the rotating photosensitive drum 31, and a bias potential applied to the developing roller 21 by a bias voltage applying device (not shown) causes the writing device (not shown) to write the photosensitive drum 31. The electric charge of the electrostatic latent image formed thereon attracts and is developed. It should be noted that the residual toner after the completion of the development is again contained in the casing 30 and mixed with the new toner, as described above.

Here, the contact pressure between the blade 22 and the developing roller 21 becomes excessive when the required rotational load torque of the developing roller 21 exceeds 3.5 kgfcm.
It needs to be 0 gf / mm or less. Also, blade 2
The radius of the arc portion at the free end of No. 2 is set to 0.5 to 1.5 mm in order to obtain a necessary toner layer thickness and charge amount.

The developing roller 21 has a toner supply roller 23 at a position downstream of the developing area of the photosensitive drum 31 in the rotation direction.
A sheet member 36 is disposed on the upstream side in the rotation direction from the pressure contact position with the sheet member 36 to uniformly contact the developing roller 21 in the longitudinal direction to prevent toner leakage. This sheet material 36
Is made of, for example, urethane rubber or pet film.

The developing roller 21 has a blade 22
At both ends of the position where the sheet comes into pressure contact, toner sealing means (developer sealing means) 37 for preventing leakage of toner is provided.

The toner sealing means 37 includes the developing roller 21
Frictional resistance is increased due to contact with the rubber portion of Therefore, nitrile rubber, acrylic rubber, silicon rubber,
It is formed of an elastic material such as a rubber material or a resin material having good slidability and abrasion resistance such as fluororubber and tetrafluoride resin. As shown in FIG. 4, the blade 22 is integrally attached to both ends in the longitudinal direction of the blade 22 and is fixed by an adhesive such as an adhesive or a double-sided tape. Therefore, the blade 22 and the toner sealing means 37 are unitized.

As a result, the positioning for filling the gap between the blade 22 and the developing roller 21 in the toner sealing means 37 is more reliable than in the conventional case where a sponge material or the like is stuck to the casing with a double-sided tape or the like. Done. Therefore, a gap generated between the blade 22 and the developing roller 21 due to a sticking error, a dimensional error of the casing, or the like can be filled, and toner leakage can be prevented.

In addition, it is not necessary to attach the toner seal means 37 to a portion where it is difficult to work inside the casing 30, so that workability can be improved and work steps can be reduced.

Here, as shown in FIG. 5, a part of the toner seal means 37 is shaped so that the end of the blade 22 fits (FIG. 5, reference numeral 37a), and the toner seal means 37 and the blade 22 fit. They may be configured so as to match each other, and both may be fixed with an adhesive, a double-sided tape, or the like.

Thus, the developing roller 21 and the blade 22 which could not be completely filled with the sponge material
Can be filled, and the leakage of toner can be reliably prevented. In addition, since both are fitted, it is possible to improve the mounting accuracy.

The blade 22 is pressed against the developing roller 21 to reduce the thickness of the toner on the developing roller 21.
When external force is applied to the product, the specified layer thickness cannot be obtained.
Alternatively, there arises a problem that a uniform layer thickness cannot be formed.

Therefore, as shown in FIG. 6, the toner seal means 37 has a predetermined amount (for example, 0.5 mm or more) of gap so that there is no portion in contact with the casing 30 within the range of the layer thickness regulation by the blade 22. 37d are formed. As a result, the blade 22 is attached to the toner sealing means 37.
, The influence of the casing 30 is eliminated, so that a uniform layer thickness can be stably formed.

Here, as described above, conventionally, when the toner seal means 37 is incorporated in the casing 30, it is fixed with a double-sided tape or the like. When the toner sealing means 37 is fixed to the casing 30 using a double-sided tape,
There has been a problem that re-pasting cannot be performed even if a pasting error or defect occurs.

Therefore, in the present embodiment, as shown in FIG. 6, for example, the width of the portion of the toner sealing means 37 in contact with the casing 30 in the circumferential direction is 0.5 to 3.0 m.
m, the height is about 0.3 to 1.0 mm.
Are formed, and a concave portion (not shown) is formed in a portion facing the convex portion 37b, and they are press-fitted and fitted to each other. Note that the unevenness may be reversed.

This eliminates the need for fixing with a double-sided tape or an adhesive, and facilitates incorporation and reassembly. Further, since both are press-fitted, the leakage of the toner can be prevented even in this portion.

Further, as shown in FIG. 6, the toner seal means 37 is carried away by the rotation of the developing roller 21 on the side of the casing 30 opposite to the end where the blade 22 of the toner seal means 37 is mounted. In order to prevent this, a rotation preventing convex portion 37c also serving as positioning is formed. A detent (not shown) is formed in a portion of the casing 30 facing the convex portion 37c, and both are press-fitted.

Here, the toner sealing means 37 is made of nitrile rubber, acrylic rubber, silicon rubber, fluoro rubber, tetrafluoride resin, or the like. It is set to 1 to 0.8. If the coefficient of friction is too low, the developer tends to enter and toner leaks easily. If it is too high, problems such as an increase in load torque of the developing device and an increase in heat due to friction occur. Then, in order to reduce such a coefficient of friction, a Niftron coat is applied to a portion of the toner sealing means 37 which comes into contact with the developing roller 21.

Next, as shown in FIGS. 7 to 9, the toner sealing means 37 is provided with a convex rib portion 37e which is inclined inward with respect to the developing roller shaft on the inner peripheral side. It can be configured to make contact.

As a result, the contact area between the toner sealing means 37 and the developing roller 21 can be minimized, and an increase in load torque and an increase in frictional heat can be prevented.

In this embodiment, the height of the convex rib portion 37e is about 0.5 to 2.0 mm and the width thereof is 0.5 to 2.0 mm.
From 1.5 mm, and the falling angle of the convex rib 37e is 30 to 60 degrees. The amount of the protrusion rib portion 37e biting into the developing roller 21 is 0.1 to 0.8 mm.

The convex rib portion 37e provided on the toner sealing means 37 is provided inside the toner sealing means 37 at an angle so that the toner is pushed back inside the casing 30 with respect to the rotation of the developing roller 21. ing.

When the toner accumulates on the back of the convex rib portion 37e, the toner is always heated by frictional heat, so that the toner is melted and fixed. Thus, if the convex ribs 37e which are inclined so that the toner is pushed back inside the casing 30 with respect to the rotation of the developing roller 21 are formed in the toner sealing means 37, nothing is present on the back surface. Therefore, the toner does not accumulate in this portion, the thermal damage to the toner is eliminated, and the problem of toner sticking can be solved.

Here, the convex rib portion 37e of the blade 22 and the toner sealing means 37 which comes into contact with the developing roller 21 is used.
When the blade 22 is higher than the toner sealing means 37 with respect to the developing roller 21, the toner sealing means 3
A gap is formed between the convex rib portion 37e of No. 7 and the developing roller 21, and toner leakage occurs. Conversely, the toner sealing means 3
If the convex rib portion 37e is higher than the blade 22, a gap is formed between the blade 22 and the developing roller 21 to cause toner leakage.

Therefore, in the present embodiment, the blade 22 and the convex rib 37e of the toner sealing means 37 are arranged on the same circumference with respect to the developing roller 21 in a state where they are assembled. . As a result, the gap between the developing roller 21, the blade 22, and the toner sealing means 37 can be filled, and toner leakage can be prevented.

Further, when the toner sealing means 37 and the blade 22 are adhered, the toner may enter both ends of the blade 22 through a small gap therebetween.

Therefore, with respect to the rotation of the developing roller 21, the convex rib portion 37e of the toner sealing means 37 is located outside the layer thickness regulation range of the blade 22 on the upstream side and in the layer thickness regulation range of the blade 22 on the downstream side. It is configured to be located inside.
Thereby, the toner that has entered the gap and leaked to the end of the blade 22 can be returned to the inside of the casing.

In the present embodiment, urethane rubber, pet film, or the like is used as the material of the sheet material 36.
Its thickness is set to 0.05 to 1.0 mm. The sheet material 36 is adhered to the casing 30 with a double-sided tape or the like, and the leading end thereof is configured to be in contact with the surface longitudinal direction of the developing roller 21. The convex rib portion 37e of the toner sealing means 37 also has a thickness of 0.1 to 1.0 with respect to the sheet material 36.
It is configured to have a region where the sheet material 36 and the convex rib portion 37e of the toner sealing means 37 intersect with the circumferential direction of the developing roller 21.

As a result, it is possible to prevent the toner sealing means 37 from being carried away by the developing roller 21 so that the toner cannot be sealed. Further, the gap between the sheet material 36 and the toner sealing means 37 can be reliably filled without using other members.

[0068]

As described above, according to the present invention, the gap between the developer layer thickness regulating means and the developing roller can be filled, so that the blade is used as the developer layer thickness regulating means. Thus, it is possible to prevent the developer from leaking in the developing device.

Further, according to the present invention, since it is not necessary to attach the developer sealing means, it is possible to obtain an effective effect that the workability can be improved and the number of work steps can be reduced.

If both ends of the developer layer thickness regulating means are fitted and fixed to the developer sealing means, it is possible to reliably fill the gap between the developer layer thickness regulating means and the developer sealing means. Effective effects can be obtained.

If a gap is formed between the developer sealing means and the casing within the range of the layer thickness regulation by the developer layer thickness regulating means, the developer layer thickness regulating means influences the casing via the developer sealing means. As a result, an effective effect of being able to stably form a uniform layer thickness is obtained.

If the developer sealing means and the casing are fixed to each other by the concave and convex fitting, the developer sealing means can be easily assembled and reassembled into the casing, and the leakage of the developer at the joint portion between them can be prevented. Is obtained.

By adjusting the coefficient of friction of the portion of the developer sealing means in contact with the developing roller to a predetermined value, the developer enters between the developer sealing means and the developing roller and the load torque of the apparatus increases. An advantageous effect is obtained that it is possible to prevent such troubles from occurring.

If the convex rib portion is formed, the developer sealing means comes into contact with the developing roller at the edge of the convex rib portion.
An effective effect of minimizing the contact area between the two and preventing an increase in load torque and an increase in frictional heat can be obtained.

If the convex rib portion is formed inside the developer sealing means so as to be inclined so that the developer is pushed back to the inside of the casing, the same developer continues to stay around the developer sealing means, and this remains. An effective effect of being able to prevent sticking due to frictional heat is obtained.

If the developer layer thickness regulating means and the convex rib portion are formed on the same circumference with respect to the developing roller, a gap may be left between the developer sealing means and the developing roller, or the developer layer thickness may be reduced. An effective effect of preventing a gap from being formed between the regulating means and the developing roller can be obtained.

With respect to the rotation of the developing roller, the convex rib portion is located outside the layer thickness regulation range of the developer layer thickness regulation means on the upstream side, and on the downstream side of the layer thickness regulation range of the developer layer thickness regulation means on the downstream side. If formed inside, the developer leaking from the end of the developer layer thickness regulating means through the gap between the developer sealing means and the developer layer thickness regulating means can be returned to the casing. The effect is obtained.

By arranging the leading end of the sheet material so as to be in contact with the longitudinal direction of the surface of the developing roller and forming a region intersecting the circumferential direction of the developing roller with the convex rib portion, the developer seal can be formed. It is possible to prevent the means from being removed due to the friction of the developing roller and to make sealing impossible, and it is possible to obtain an effective effect that the gap between the sheet material and the developer sealing means can be reliably filled.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an image forming apparatus equipped with a developing device according to an embodiment of the present invention;

FIG. 2 is a sectional view showing a process unit including a developing device attached to the image forming apparatus of FIG.

FIG. 3 is an enlarged sectional view showing a main part of FIG. 2;

FIG. 4 is a perspective view showing an example of a toner seal unit and a blade attached to the image forming apparatus of FIG. 1;

FIG. 5 is a perspective view showing another example of the toner seal unit and the blade attached to the image forming apparatus of FIG. 1;

FIG. 6 is a perspective view showing still another example of the toner seal unit and the blade attached to the image forming apparatus of FIG. 1;

FIG. 7 is a perspective view showing still another example of a toner seal unit and a blade attached to the image forming apparatus of FIG. 1;

8 is an enlarged perspective view showing a main part of FIG. 7;

FIG. 9 is a plan view of FIG. 7;

[Explanation of symbols]

 Reference Signs List 21 developing roller 22 blade (developer layer thickness regulating means) 23 toner supply roller (supply roller) 30 casing 31 photoconductor drum (photoconductor) 36 sheet material 37 toner seal means (developer seal means) 37e convex rib portion

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Homan 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Tosumi Hattori 1006 Kadoma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshihiro Mizoguchi 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshiaki Ijima 1006 Odaka, Kazuma, Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. 1006 Kadoma, Kadoma, Fumonma Matsushita Electric Industrial Co., Ltd. F-term (reference) 2H077 AC04 AD02 AD06 AD13 AD17 BA08 CA12 EA14 FA22 FA26

Claims (10)

[Claims] A developing roller that supplies a developer to an electrostatic latent image formed on a photoconductor to visualize the electrostatic latent image; a supply roller that supplies the developer to the developing roller; The developing roller and the supply roller are rotatably mounted and a casing in which the developer is stored, and the developing device is mounted on the casing so as to press and contact the developing roller, and is supplied to the developing roller. A plate-like developer layer thickness regulating means for regulating the layer thickness of the developer, and a rotation direction downstream side of the developing region of the photoconductor in the developing roller and a rotation direction upstream side of a pressure contact position with the supply roller. A sheet material for uniformly abutting in the longitudinal direction of the developing roller to prevent the leakage of the developer; and a sheet material integrally attached to the developer layer thickness regulating means. Serial developer layer thickness regulating means is provided at both ends of the position where the pressure contact, developing device and having a developer sealing means for preventing leakage of the developer made of an elastic material. 2. The developing device according to claim 1, wherein both ends of said developer layer thickness regulating means are fitted and fixed to said developer sealing means. 3. The apparatus according to claim 1, wherein a gap is formed between the developer sealing means and the casing within a range of the layer thickness regulated by the developer layer thickness regulating means. Developing device. 4. The developing device according to claim 1, wherein said developer sealing means and said casing are fixed by fitting in a concave and convex manner. 5. A coefficient of friction of a portion of said developer sealing means in contact with said developing roller has a dynamic friction coefficient of 0.1 to 0.1.
The developing device according to claim 1, wherein the number is eight. 6. A developing device according to claim 6, wherein said developer sealing means has a convex rib portion orthogonal to said developing roller shaft and inclined inwardly formed on an inner peripheral side in contact with said developing roller. Item 6. The developing device according to any one of Items 1 to 5. 7. The developer sealing device according to claim 6, wherein the convex rib portion is formed inside the developer sealing means so as to be inclined so that the developer is pushed back inside the casing. Developing device. 8. The developing device according to claim 6, wherein said developer layer thickness regulating means and said convex rib portion are formed on the same circumference with respect to said developing roller. 9. The rotation of the developing roller is such that the upstream side of the convex rib portion is outside the layer thickness regulating range of the developer layer thickness regulating section, and the downstream side is the developer layer thickness regulating section. 9. The developing device according to claim 6, wherein the developing device is formed inside the layer thickness regulation range. 10. A front end of said sheet material is arranged so as to be in contact with a longitudinal direction of a surface of said developing roller, and said sheet material and a convex rib portion have a region which also intersects with a circumferential direction of said developing roller. The developing device according to claim 6, wherein: